Field of the Invention
The invention relates to a ring spinning machine in which conveyor belts drivable for delivering empty tubes and removing cops are disposed along spindle rows present on both sides of the machine, the conveyor belts having openings at half the spindle spacing for receiving arbors for cops and empty tubes in alternation.
A ring-spinning machine of this generic type is known for example from German published, non-prosecuted application DE-OS 20 45 263. An essential characteristic of such a ring-spinning machine is that conveyor belts are disposed on both sides of the machine along the rows of spindles. The conveyor belts deliver empty tubes to the spinning machine and remove cops therefrom. The conveyor belts have openings at half the spindle spacing at which alternatingly arbors for cops and for empty tubes are secured. Typically, the arbors are secured in these openings by screw fastening means. One advantage of this is that in doffing, an intermediate position for the empty tubes is not required. Thus the full cops are first removed from the spindles by the doffer and placed directly on the arbors, intended for that purpose, between the empty tubes that are located on the respectively other arbors. Immediately after that, by indexing the conveyor belts onward by one-half the spindle spacing, the empty tubes are positioned under the grippers of the respective doffer. The doffer can then immediately grasp these empty tubes and place them on the empty ring spindles. This doffing process can be achieved very reliably and quickly. However, in this embodiment, the transport path of the cops and tubes is bound to the transport path of the respective conveyor belts.
To overcome that bound condition, it has heretofore been proposed in European patent publication EP 0 410 121 B1 to provide slideways all around the ring-spinning machine, on which, by means of a conveyor chain having drivers, caddies independent of one another (transport plates) can be displaced. These caddies can be spun out of this transport loop along with the cops or tubes placed on them. The center spacing of the caddies is equivalent to the spindle spacing. To enable carrying out the doffing operation, additional spindles are also present on the drivers. In the doffing process, the tubes first removed from the caddies have to be transferred to this intermediate position so that the arbors of the caddy will be freed for mounting the removed cops on them. Then the doffer must take over the "temporarily stored" empty tubes and mount them on the ring arbors. This doffing operation is more complicated than the one described in the above-noted German publication 20 45 263.
European published, non-prosecuted application EP 0 355 887A1 describes a spinning machine in which the intermediate position is avoided by using caddies with two arbors. These caddies are coupled to one another, resulting in one coherent train. However, that cancels out the mutual independence of the caddies. Above all, it becomes problematic to control this coherent caddy train if it is used in ring-spinning machines with more than 40 spinning stations, as in the exemplary embodiment of EP 0 355 887 A1, as for example 1000 or more. Above all, because dimensional deviations add up, by the end of the train there can be such a difference in spindle spacing that major damage can occur in the doffing process.
The same problem arises if, as in the example in Japanese patent application 64-28175, a pusher unit of caddies coupled together in pairs is formed.
The Japanese patent abstract JP 62-257429 pertains to a conveyor belt with entraining members 12 which engage in relatively large openings at the bottom of peg trays. The spindle spacing of the spinning machine corresponds to the diameter of the peg trays. Accordingly, the transport system cannot be utilized in doffing systems without intermediate storage of the empty tubes.